The spnego_gss_accept_sec_context function in lib/gssapi/spnego/spnego_mech.c in MIT Kerberos 5 (aka krb5) 1.5 through 1.6.3, when SPNEGO is used, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via invalid ContextFlags data in the reqFlags field in a negTokenInit token.
https://www.redhat.com/archives/fedora-package-announce/2009-April/msg00206.html
https://www.redhat.com/archives/fedora-package-announce/2009-April/msg00205.html
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A6449
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A10044
https://exchange.xforce.ibmcloud.com/vulnerabilities/49448
http://www.vupen.com/english/advisories/2009/2248
http://www.vupen.com/english/advisories/2009/1297
http://www.vupen.com/english/advisories/2009/1106
http://www.vupen.com/english/advisories/2009/1057
http://www.vupen.com/english/advisories/2009/0976
http://www.vupen.com/english/advisories/2009/0847
http://www.us-cert.gov/cas/techalerts/TA09-133A.html
http://www.ubuntu.com/usn/usn-755-1
http://www.securitytracker.com/id?1021867
http://www.securityfocus.com/bid/34257
http://www.securityfocus.com/archive/1/502546/100/0/threaded
http://www.securityfocus.com/archive/1/502526/100/0/threaded
http://www.redhat.com/support/errata/RHSA-2009-0408.html
http://www.mandriva.com/security/advisories?name=MDVSA-2009:082
http://www.kb.cert.org/vuls/id/662091
http://www-01.ibm.com/support/docview.wss?uid=swg21396120
http://wiki.rpath.com/wiki/Advisories:rPSA-2009-0058
http://wiki.rpath.com/Advisories:rPSA-2009-0058
http://web.mit.edu/kerberos/advisories/MITKRB5-SA-2009-001.txt
http://support.novell.com/docs/Readmes/InfoDocument/patchbuilder/readme_5047181.html
http://support.novell.com/docs/Readmes/InfoDocument/patchbuilder/readme_5047180.html
http://support.avaya.com/elmodocs2/security/ASA-2009-142.htm
http://support.apple.com/kb/HT3549
http://sunsolve.sun.com/search/document.do?assetkey=1-26-256728-1
http://src.mit.edu/fisheye/changelog/krb5/?cs=22084
http://security.gentoo.org/glsa/glsa-200904-09.xml
http://secunia.com/advisories/35074
http://secunia.com/advisories/34734
http://secunia.com/advisories/34640
http://secunia.com/advisories/34637
http://secunia.com/advisories/34630
http://secunia.com/advisories/34628
http://secunia.com/advisories/34622
http://secunia.com/advisories/34617
http://secunia.com/advisories/34594
http://secunia.com/advisories/34347
http://lists.apple.com/archives/security-announce/2009/May/msg00002.html
http://krbdev.mit.edu/rt/Ticket/Display.html?user=guest&pass=guest&id=6402